Process of and apparatus for converting cast-iron into cast-steel



- (No Mode1.)

E J REESE.

PROCESS OF AND APPARATUS FOR CONVERTING CAST IRON INTO CAST STEEL. No.277,929. Patented May 22,1883.

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UNITED STATES PATENT OFFICE.

JACOB REESE, OF PITTSBURG, PENNSYLVANIA.

PROCESS OF AND APPARATUS FOR CONVERTING CAST-IRON INTO CAST-STEEL.

SPECIFICATION forming part of Letters Patent No. 277,929, dated May 2 2,1883.

Application filed February 11, 1881. (No model.)

To all whom it may concern:

Be it known that I, JACOB REESE, of the cityof Pittsburg, in thecountyof Allegheny andSta-te of Pennsylvania, have invented a new and usefulImprovement in Apparatus for and Process of Gonvertin g Cast-Iron intoGast- Steel; and I do hereby declare the following to be afull,clear,and exact description thereof. In the metallurgy of iron and steel thereare two distinct processes by which cast-iron may be converted intocast-steel while the-metal is held in a continuous molten condition,each of which possesses essentially different characteristics andproduces a metal of different physical properties.

The Bessemer process is conducted in a vessel in which no other fuel isused than that contained in the metal. The metalloids are eliminated byoxidation secured by oxygen from a blast of air. When the metalloids areall consumed, there being no other source from which to develop thecaloric necessary to keep up-fluidity, the metal must be immediatelyemptied out of the vessel to prevent chilling. The physical structure ofBessemer metal so produced is cellular, porous, and spongy, owing to thegases which were occluded while the metal was blown.

The open-hearth process is conducted in a vessel in which other fuel isused than that contained in the metal. The metalloids are oxidized byoxygen supplied by metallic oxides. By the combustion of other fuel themetal may be kept in the vessel in a high condition of fluidity andastate of rest after the metalloids are all consumed. By virtue of thisrefining period, the metal being highly fluid, there be ing noebuilition, the gases escape, the cells are closed and welded, and themetal, When' cast, exhibits a solid homogeneous structure peculiar to ametal which has been subject to what the workmen term a dead melt.

Ten tons of cast-iron may be converted into cast-steel by the Bessemerprocess in twenty minutes, while a like quantity cannot be converted bythe ordinary open-hearth process in less than ten hours. The cost ofconverting by the Bessemer is somewhat less than by the open-hearthprocess; still, owing to the improved product, the open-hearth processis being generally introduced.

The object of this invention is to combine the distinctivecharacteristics of the Bessemer and open-hearth processes into one, witha view of securing the rapid elimination of the metalloids incident tothe Bessemer process and the period of rest and resulting homogeneousphysical properties of metal produced tion of high fluidity and at astate of rest until the. gases escape, whereby its porosity is reducedwhen cast into ingot-iron; or, if steel is desired,I may recarburizethefluid iron and hold the steel in a condition of high fluidity and at astate of rest until the gases escape and the porosity of the metal isreduced, and then pourit into ingots or suitable molds. The period ofrest will not ordinarily exceed fitteen or twenty minutes. Thus ten tonsof cast-iron may by my improvement be converted into cast-steel in fromthirty to forty minutes, and the resulting metal will possess all thedesirable characteristics of the product of the open-hearth process.

The improved apparatus consists of a Bessemer converter having two openor hollow trunnions, with accompanying conduits, leading into thetuyere-box. The tuyere-box is divided into two distinct air-tightcompartin en ts, each compartment being connected with only one of theconduits leading to the trunnions. Each compartment of the tuyere-boxcommunicates with the interior of the converter by means of tuyeres inordinary use. The pipes leading to the trunnions are provided withvalves, by which the air-blast may be permitted to enter both trunnionsand both divisions of the tuyere-box, or either of them, at the will ofthe metallurgist.

nected with a pipe leading to a producer of a carbureted vapor. Thesepipes are also provided with valves, in order to enable the metallurgistto force the vapor of carbon, hydrocarbon, or carbonic oxide into oneorreither 0t thedivisions of the tuyere-box, or to exclude Each of the'pipes leading to the trunnions is also conare reduced to the desireddegree, then turn- "condition during "further treatment.

ing the converter down until the tuyeres are above the molten mass, thenforcing a vapor of carbon or other combustible gas into and through oneportion of the tuyeres and an equivalent amount of air through the otherportion of the tuyeres, whereby combustion takes place in the converterabove the molten metal, and the metal is kept in a highly fluid steel isdesired the metalloids are eliminated as before described. Theconverteris then turned down, the metal then deoxygenized, recarburized, and asmall portion of silicon added, the gas and air let on, and the metalkept in a state of rest and acondition of high fluidity for from fifteento twenty minutes, whereby the metal is refined, the gases escape, andthe silicon protectsthe carbon from oxidation, so that a definitepercentage of carbon may be found in the resulting metal,though themetal be subjected to the refining period after recanbnrization. Themetal, after the refining period of rest, is run into ingots, which willbe comparativel y free from porosity an d be homogeneous.

Another feature of the improved process which forms a part of thisinvention is the production of different grades or qualities of steelfrom the same heat or blow of the converter, which I am able to effectin the following manner: In case a heat of steel is desired to beconverted into different degrees of car burization for the purpose offilling dilferent orders of merchant or agricultural steels, or in theproduction of steel castings of different degrees of density orductility, I blow the metal until the metalloids are eliminated, thenturn the converter down and deoxygenize and recarburize the metal to thelowest degree of carbon desired. The gases are then let in,and after theperiod of rest is had I pour out such quantity as desired of that grade.I then recarburize the remainder to a higher degree and pour suchquantity of that grade desired, and by a similar treatment producedifferent degrees of carbon, until the metal is all utilized. Duringthis treatment care must be taken to keep up the temperature by a livelycombustion, so that the metal may be kept in ahighly fluidstate, andsufficient silicon should be added to keep the degree or percentage ofsilicon in the metal continuously above .020.

. In the drawings, Figure 1 represents a converter in a blowingposition, partly in section. It shows the air or gas pipes or conduitsleadingfrom each trunnion into the double-chambered tuyere-box. Thetuyere-box being in section,the division-plate is shown. Fig. 2indicates the converter turned down in a refining position. It isalongitudinal section. Fig.

When

3 is plauview of the tuyere-box and connecting air or vapor pipes. Fig.4 is a sectional view of the branch air and vapor pipes and theirvalves.

It will be observed that an air-blast is blown into both divisions ofthe tuyere-box when the converter is in a vertical position, as shown inFig. 1, and when the converteris in the horizontal position, as shown inFig. 2, air-blastis admitted into one division of the tuyere-box and thecombustible vapor in the other, so that the air-blast first used passesthrough the metal, as in the ordinary Bessemer practice, while thecombustion and resulting gases pass over the metal, as in theopen-hearth practice.

gas-producers, such as now used in the openhearth practice, or by anyother suitable means. The gas should be forced into the converter bymeans of a pressure-blower, in order to secure the necessary volume; butcare should be taken that the pressure of the blast or the gas be not sogreat as to prevent a perfect combustion inside of the converter. Thequantity of heat developed may be regulated by the quantity of gas andair blown in, and the quality of the flame may be regulated by supplyingjust sufficient air to consume the carbon to carbonic oxide, (00,) or inquantity to consume it to carbonic acid, (00

The advantages secured by the practice of this invention are, first,combining the desirable features of the Bessemer and open-hearthprocesses into one; secondly, by conducting the combined process in aBessemer converter the time of treatment is not much greater than theBessemer, and much less than by the open hearth third, the loss of metalincident to transferring Bessemer metal to an open hearth is avoided,and the metal may be poured out of the converter, avoiding the loss ofmetal in cleaning out the open hearth; fourth, the converter may be morereadily heated and kept in a heated condition during theinterval betweendifferent heats; fifth, the metal may be keptin the converter for anylength of time before being blown or after being blown and refined.

I am aware that the ,tuyere-box of a converter has heretofore beendivided into separate compartments in order to reduce the vol ume andcontrol the directionof the air-blast,

and also to introduce air and gas at separate points, and I do not claimthe same; but I am not aware that provision has heretofore been madewhereby the gas could be admitted to either compartment, or that the airand gas have been admitted to the converter above the molten metaltherein to produce and maintain combustion, obtain a state of rest anddead melt, and permit the escape of occluded gases after decarburizationand desiliconization.

I am also aware that after desiliconizing and decarburizing charges ofmetal the same have been subjected to an over melt" in an independentfurnace in order to obtain a homogeneous mass for castings and similarpurposes,

The gas may be secured by the use of the ordinary the vessel so that thetuyeres are above the molten mass, and forcing into the vessel a streamof gas or combustible vapor and an equivalent amount of air or oxygen,whereby combustion is secured above the metal, and the metal is held ina highly fluid state during the period of further treatment,substantially as and for the purpose described.

2. The method herein described of producing a metal free fromblow-holes, which consists in the introduction of combustible gases andair into the converter above the contained molten metal afterdecarburization and desiliconization, whereby a state of rest or deadmelt of the metal in the converter is obtained and the escape ofoccluded gases permitted, substantially as and for the purposespecified.

3. The combination, with a converter havin g its tuyere-box divided intoseparate com-' partments, of independent blast-pipes leading from thetrunnions to the respective compartments, and branch pipes communicatingwith the blast-pipes, the branch pipes being provided with suitablevalves, whereby air or gas may be admitted to either compartment ofthetuyere-boX, substantially as and for the purpose specified.

In testimony whereof I have hereunto set my handthis 1st day ofFebruary, A.D. 1881.

. JACOB REESE.

Witnesses:

JOHN M. BOURKE, F. G. MCGIRR..

